1. Field of the Invention
The present invention relates to an oil tank for use in a lubricating system of a drive sump type internal combustion engine. The oil tank of the present invention is simplified in both structure and in its requirements of manufacture.
2. Background Art
In a drive sump type internal combustion engine, an oil tank is provided separately from an engine and is connected through hoses to a feed pump and a scavenging pump disposed on the side of an engine. For example, in Japanese Published Examined Patent Application No. H4-31915, a conventional oil tank is shown disposed behind an engine and supported separately from the engine by a vehicle body frame.
If an oil tank is disposed separately from an engine as in the conventional art, the oil tank and the engine must be each connected to a vehicle body frame through a mount and a hose. This arrangement results in an increased number of assembling steps and more complicated assembling and mounting methods. If oil is to be fed to a hydrostatic type continuously variable transmission, the oil tank required becomes fairly large in size and the provision of such a large-sized oil tank becomes cumbersome in the layout of a vehicle body.
The present invention overcomes the shortcomings associated with the prior art and achieves other advantages not realized by the prior art.
Accordingly, it is an object of the present invention to provide an oil tank that is simplified in structure and requires relatively few assembling steps in comparison to the devices of the conventional art.
A further object of the present invention is to provide an oil tank that helps to increase system efficiency by facilitating cooling of lubricants within a lubrication oil system.
A further object of the present invention is to provide an oil tank that reduces power requirements for the pumping of oil within a lubrication system.
A further object of the present invention is to provide an oil tank that can be installed in a position that reduces cumbersome hoses and fittings associated with separately mounted oil tanks of the conventional art.
These and other objects are accomplished by a lubricating system for a power unit comprising an oil tank; at least one oil pan for an internal combustion engine; a feed pump for feeding lubricating oil in the oil tank to a plurality of components in the power unit; at least one scavenging pump for feeding oil which has stayed in the oil pan back to the oil tank; wherein said oil tank for the power unit is mounted directly to a side portion of the power unit; and a hydrostatic type continuously variable transmission, wherein the oil tank feeds oil to the hydrostatic type continuously variable transmission.
These and other objects are also accomplished by a lubricating system for an internal combustion engine comprising an oil tank; at least one oil pan for the internal combustion engine; a feed pump for feeding oil in the oil tank to a plurality of portions in the internal combustion engine to be lubricated; at least one scavenging pump for feeding oil which has stayed in the oil pan back to the oil tank; wherein said oil tank for the internal combustion engine is mounted directly to a side portion of the internal combustion engine via a mounting seat; a bearing portion for housing a bearing of the crankshaft; an inlet in communication with a suction side of the feed pump; an outlet in communication with a discharge side of each scavenging pump, wherein said inlet and said outlet are both formed in a position vertically beneath said bearing portion and in direct communication with a lower portion of the oil tank; a lower portion; an upper portion; a front side portion and a rear side portion; a left side portion and a right side portion; an initial cooling passage extending from said lower portion to said upper portion along said rear side portion, wherein said initial cooling passage is connected to an outlet in communication with the discharge side of each scavenging pump; an upper end portion of the initial cooling passage is in communication with a horizontal passage extending from said rear side portion of the tank to said front side portion of the tank; and a front end of the horizontal passage is formed as a discharge port connected to an oil cooler.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.